He is more of a small forward.
Actually I can see him playing a Draymond Green type role, even though is a little smaller than Green.
Culver is 6'5", 195 pounds, which is tiny for a small forward. Booker is bigger at 6'6", 210 pounds. Heck, Troy Daniels, while an inch shorter at 6'4", outweighs Culver at 200 pounds. Tyler Johnson is 6'4" 190 pounds. I see Culver as a slightly bigger, worse shooting version of Tyler Johnson.
Green is 6'7", 230 pounds. Unless Culver grows 2 inches, gains 35 pounds of muscle, learns to shoot the three and suddenly learns how to pass, there is zero chance of Culver playing a Draymond Green type role. Best case scenario for Culver is Tony Allen, and we already have Booker, Bridges, Jackson (who is a taller, bigger, stronger, more talented version of Culver) and even Tyler Johnson to play the 2, while we hopefully have Oubre, Bridges and Jackson to play the 3.